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Cannabis 101

How to Prevent Mold While Storing Cannabis

March 27, 2017
This article is sponsored by Integra by Desiccare. Integra™ by Desiccare manufactures a complete line of humidity control products for the cannabis industry.  Whether you’re drying, curing, storing, or preserving edibles, they have the solution to keep the freshness, potency, taste, and overall quality of your product. 

Cannabis storage has come a long way since the days of plastic bags. But even with improved packaging, freshness is not the only thing that should concern you. Mold, which can develop in storage, not only threatens the health of your cannabis — it can threaten your health as well. What are the dangers of moldy cannabis, and how can you keep your products free of mold completely?

Causes of Cannabis Mold During Storage

Marijuana Bud Clippings Harvested From the Plant Commercial Grow Operation

When cannabis is taken from the curing room, it is generally free from mold as long as the producer has taken the necessary precautions in preventing it. At this point, however, the cannabis will be transferred to containers and this is when it can be exposed to higher humidity levels. This exposure to humidity will persist for the life of your product as you continually open and close the product’s container. This will also put your product at risk of mold.

There are two types of mold you hear about when discussing impacts to consumer’s health. The first, more commonly found while your cannabis is in production, is known as “bud rot” or Botrytis cinerea. The second is Aspergillus.

  • Botrytis cinerea is known for its destruction of the cannabis plant itself. It works from the stem outwards, starting as grayish-white wisps that eventually kill the bud, turning a dense cola into squishy, moist plant matter. Bud rot is only found on the plants and is most common in dense colas that receive little airflow and can retain moisture. It cannot develop on cannabis plants after they have been harvested.
  • Aspergillus is a very common mold that can be found on more than just the buds of the plant. When found in high concentrations in the air, Aspergillus spores can wreak havoc on those with damaged lungs or weakened immune systems. It is commonly found in soil or anywhere with a high moisture content, including the buds of a cannabis plant. Unlike bud rot, Aspergillus can affect cannabis plants during storage.

Mold’s Effects on Cannabis and Human Health

Tired business woman at workplace in office

When your cannabis is exposed to mold, it is rendered useless. Smoking a cannabis product with mold can cause serious harm to the consumer, especially if they have a compromised immune system. As cannabis pushes forward as a medical product, the concern surrounding mold and contaminants is of utmost importance. Cannabis with mold should be discarded in its entirety to protect consumer health.

Cannabis with high levels of Aspergillus can result in harmful infections. High concentrations can lead to the development of an aspergilloma, which can cause symptoms ranging from a basic cough to severe fatigue and hemoptysis. To those with weakened immune systems, Aspergillus exposure can turn into invasive pulmonary aspergillosis, which can spread to other parts of the body besides the lungs, and is capable of resulting in death if not treated properly.

Cannabis with bud rot also contains spores that can cause damage to your lungs, yet bud rot is not associated with risks as severe as Aspergillus.

Preventing Mold when Storing Cannabis


The best way to prevent mold while storing cannabis is to provide a consistent dry environment for your product. For most consumers, air-tight “nug jugs” are a sufficient option. However, as discussed previously, continued exposure to humid outside air can lead to mold development.

You can guarantee your product is stored safely is through the use of a humidity packet. Integra produces Boost packets in two different forms for this purpose: One packet ensures 62% relative humidity (RH) while the other ensures 55% RH. You can select a packet based off personal preference when it comes to how dry you want your product, but both will keep your cannabis protected from higher humidity levels that can result in mold growth. Additionally, the packets have indicator strips that will inform you when the packets need to be replaced to further guarantee that the quality of your cannabis is protected.

3 part series

  • Demented Son

    these are great I buy them on ebay all the time

  • Glen Urquhart


    • Robert

      Steal Your Face! 🙂

      Huge Dead fan here (San Francisco here)

    • DonKilo

      Curious.. Why don’t you offer a humidity pack in your jars?

  • Thomy

    I don’t use the packets. I just trim my bud and once it is ready for “curing”, I simply place it into those ceramic ( often porcelain ) storage canisters that have the buckle and often have a rubber gasket. As the lid is closed, air is automatically ejected, rendering the contents “air tight” meaning no air can get inside the container while the lid is closed and buckled. Once the Cannabis has been cured, I freeze it in those canisters @ 0 degrees F. I have Cannabis, stored that way today, that is at least 3 years old. One very important thing to remember when freezing Cannabis in any air tight container is keep the contents sealed until the entire canister is up to room temperature, usually about an hour but if you can leave it for 2 hours, all the better because cold or frozen contents, attract moister in the air, so you want your product fully thawed out before you ever open the canister. Remember, once cured and usable, Cannabis has 4 basic enemies air, heat, water and mold. If grown outdoors, the plants probably already contain the spores but the mold cannot grow and develop if you don’t expose it to moister, heat and air. The packets are fine but they only help keep the humidity down and their ability to absorb the moisture in air weakens with age and I doubt you’ll get 3+ years of storage using them alone. The important thing is to allow the canisters to completely thaw out before ever opening. You do this and I guarantee, that Cannabis, even though it has been stored for 3 years, will taste, smell and smoke just like it did when you originally placed it in the canister. Canisters are available at most retail stores but they’re also a common item found in thrift shoppes as well. Happy Camper in Spokane Wash.

    • alacrity

      Man, I’ve been doing much the same for around 12 years- I have a batch that my dad and I grew in ’09, that is still viable, although the CBN has increased to a level that almost ensures nap-time within an hour- and added one more step: vacuum sealing. Placing the glass jar in a vacuum pouch then cycling and sealing prior to cryo storage increases it’s life exponentially. As long as the packs are held at a steady low-temp, not jostled or mishandled- the integrity of the flower is intact, as is the efficacy. Sure, there is minor deterioration of terpines and THC- but the emphasis is on the word ‘minor’- and I can state without qualification that even flower from almost a decade of cryo-storage still works beautifully. Mold is not an issue- period.

      • Dan Hutchinson

        “I can say this without equivocation”

  • Mark Skinner

    I have found that thorough natural drying prior to freezing makes for good keeping. I’ll have to get one of the containers
    Thomy speaks of. He has obviously got it down pat. Thanks Thomy.

  • Robert

    I have glass jars and I put my buds in there with a humidity packet. Then I put ALL the jars in an air-tight silver container with a rubber gasket and a lock on it. I then put that into a chest that is dark and dry. I’m hoping I am doing it all correctly. I do have a fear of mold ALL the time and I’d like to know exactly how to know if it has it. Should I buy a magnifying glass so I can look at it – and if I do, what exactly am I looking for to know it is bad.

  • Jason Shimberg

    Bunny rabbits eat mold, that’s why we have lettuce.

  • gray lock

    The C Vault works great for me. A little pricey but the lid has a gasket and is air tight, plus has a slot for the Integra or Boveda pack.

  • Gary Growden

    Why don’t all of you use nitrogen applications – regardless of the time, temperature and humidity. This is the best technology known to prevent mold, mites and control the humidity. Get the containers and canisters from


    Forgot to mention in my other comments…..After finally storing the bud I flood the jars with Nitrogen.